// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/native_library.h"

#include <dlfcn.h>

#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_restrictions.h"

namespace base {

std::string NativeLibraryLoadError::ToString() const
{
    return message;
}

// static
NativeLibrary LoadNativeLibraryWithOptions(const FilePath& library_path,
    const NativeLibraryOptions& options,
    NativeLibraryLoadError* error)
{
    // dlopen() opens the file off disk.
    ThreadRestrictions::AssertIOAllowed();

    // We deliberately do not use RTLD_DEEPBIND by default.  For the history why,
    // please refer to the bug tracker.  Some useful bug reports to read include:
    // http://crbug.com/17943, http://crbug.com/17557, http://crbug.com/36892,
    // and http://crbug.com/40794.
    int flags = RTLD_LAZY;
#if defined(OS_ANDROID) || !defined(RTLD_DEEPBIND)
    // Certain platforms don't define RTLD_DEEPBIND. Android dlopen() requires
    // further investigation, as it might vary across versions. Crash here to
    // warn developers that they're trying to rely on uncertain behavior.
    CHECK(!options.prefer_own_symbols);
#else
    if (options.prefer_own_symbols)
        flags |= RTLD_DEEPBIND;
#endif
    void* dl = dlopen(library_path.value().c_str(), flags);
    if (!dl && error)
        error->message = dlerror();

    return dl;
}

// static
void UnloadNativeLibrary(NativeLibrary library)
{
    int ret = dlclose(library);
    if (ret < 0) {
        DLOG(ERROR) << "dlclose failed: " << dlerror();
        NOTREACHED();
    }
}

// static
void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
    StringPiece name)
{
    return dlsym(library, name.data());
}

// static
std::string GetNativeLibraryName(StringPiece name)
{
    DCHECK(IsStringASCII(name));
    return "lib" + name.as_string() + ".so";
}

} // namespace base
